Presentation on theme: "Scalars & Vectors. Scalars: Measurements that have no direction The quantity is called magnitude Ex: Distance: d, time: t, mass: m Vectors: Measurements."— Presentation transcript:
Scalars: Measurements that have no direction The quantity is called magnitude Ex: Distance: d, time: t, mass: m Vectors: Measurements that have both direction & magnitude Indicate direction with +/- sign or [N], [E], [W], [S] Must put arrow over vector symbols Ex: Displacement:,velocity:,force: Scalars vs. Vectors
During calculations, vectors that are: Up and right are positive (+ve) Down & left are negative (-ve) **But usually you specify the direction of vectors in the final “answer” (N, E, W, S) Vector Sign Conventions +ve -ve [N] [E][W] [S]
Distance (d): Length travelled by an object regardless of direction. Scalar = Always +ve Displacement ( ): Change in position of an object. = final position – initial position Vector – If ∆d = +ve, object moves right or up – If ∆d = -ve, object moves left or down ***Displacement is independent of path taken. Distance vs. Displacement
Ex: A student walks 5 m east and then 3 m west. a)What is the distance travelled? b)What is the student’s displacement? a) d = 5 m + 3 m = 8 m b) Draw the vector arrows: 5 m east 3 m west Resultant or “net” vector 2 m east When adding vectors we use the tip-to-tail method.
You try: A man walks 275 m east and then turns around and walks 425 m west. He then returns to where he started. a)What was the distance travelled by the man? b)What was the man’s displacement?